Many private communication networks, for example private automatic branch exchanges (PABX), offer services to the communication terminals connected to them. These services include in particular call forwarding, access to directories or databases, storage of messages, conference calls and voice or written notepads. These services are accessible to terminals when they are connected directly to their own private network, of course. However, if terminals are for away from the private network, they are able to access certain of their services only if said private network is connected to a public network via a communication server such as a gateway, and subject to particular arrangements.
One particular arrangement is assigning to certain keys of the terminal's keypad functions corresponding to particular services. Pressing one of these keys sends to the gateway a preprogrammed dual tone multifrequency (DTMF) data sequence on a public network transmission channel dedicated to the exchange of voice data. Consequently, if a user wishes to access a service when he has already set up a voice connection to another terminal, he must first of all temporarily break off his connection, then set up a connection with the server for the latter to make said service available to him, and finally re-establish the original connection to the other terminal. Moreover, during a voice connection with another user, this rules out dynamically offering the user services adapted to certain events that may arise during a call, for example a higher priority incoming call, a text message that needs to be displayed during a call, or a request to enter a conference call. Moreover, only the services associated with the preprogrammed functions may be made available to terminal users. This arrangement is therefore “static”, making it ill-suited to the requirements of real time processing.
A second arrangement, described in patent application EP 1 107 523, consists first of all in setting up, on a public network transmission channel dedicated to signaling, a connection between a terminal wishing to access services of its own private network and a gateway connected to that private network, and then sending a Word Markup Language (WML) page offering its user a certain number of services to the calling terminal via the gateway. When the user has made his choice, his terminal sends to the gateway a WML command and, following specific data exchange protocol format conversion processing, the terminal is able to access the chosen service. Because the user has to make his choice from a predefined list of services, it is not possible, during a voice connection with another user, to offer the user dynamically services adapted to certain events that may arise during a call. This arrangement is therefore also “static”, making it ill-suited to the requirements of real time processing.